AdGuard is one of the best ad blocker tools out there. It runs as an app and so kills ads on your browsers and more. If you use the "MMARCHSAVE" promo code on StackSocial you get a further US$5.99 off the US$29.99 price, which is already a 74% discount of the usual lifetime licence. Covers two computers (Windows or Mac) plus two Android devices. The software is separately available for free or A$2.99 (for best results) for iOS.
You can buy up to three subscriptions (each of which covers two computers). Best to buy them separately and take advantage of the "MMARCHSAVE" code each time.
I use AD Block which is free and does an awesome job..